As of this writing the mod files have been posted to moddb for everyone to enjoy. Instructions for install are on the downloads page and in the readme included with the .zip.
Any map or mission created for the original game (that is, a Viron vs NSA map) will work with this mod. Depending on version the Viron or NSA player can become Terran and so will all of their units and abilities. I've also heard of custom "Terran maps", these may or may not function as intended depending on which version of the mod you try to run them with. I make no guarantees with those.
An explanation of the three versions or sections of the mod is below. Note: All three versions have the same unit balance fixes regardless of which factions are playable.
In this mode players can choose to play as either Terrans or Virons in skirmish/MP. The campaign has been switched around so that the player has Terran units and is fighting against the NSA. In the Viron campaign they can choose to deploy either Viron or Terran units. Aside from the unit and graphics swap, the campaign is unchanged. Its a whole different experience though.
This mode is identical to the original game in that the player can choose NSA or Virons to play. The campaign is not altered in this mode either. This mode is here for anyone who wants to play a vanilla match with just the balance improvements applied.
This is the Terrans vs NSA mode for skirmish/MP. The campaign does not differ from the original in this mode either.
In each version there is an AI player that will deploy units from the missing, third faction so you can fight them. Look for the "NSA Commander" in the AI player list for example. Also make sure that you are using the same version of the mod as your friends if you decide to play the mod together.
Some of the Terran units are missing particle effects for their secondary mode. This has not been possible for me to change, but the units will still function as their decription says they do.
A cutscene halfway through the Viron campaign mission "Reptile House" will not finish if you are playing it with Reversal activated. Just skip the cutscene by hitting ESC and you can continue the mission as normal.
Feel free to post any comments or suggestions here on the moddb page. I can't guarantee that there will be another release but the feedback can't hurt.